Production of metal alloy and of articles made thereof



Patented Jan. 7, 1

UNITED-STATES WALTER SCHROBSDORFEbF BEBLIN-WESTEND, GERMANY PRODUCTION 9F METAL ALLOY AND 0] ARTICLES MADE THEREOF f Ho Drawing. Application filed July 18, 1927, Serial No. 206,791, and in Germany July 21, 1988 My invention relates to improvements in the. production of metal alloys and of articles of various kinds made thereof and Serving especially for such plulfposes as tools, implements, parts of mac cry and of apparatus, nozzles, containers etc., and being used more particularly in industries and branches of manufacture, in which raw materials and partially manufactured articles are formed,

0 shaped and otherwise worked upon under extraordinary conditions, 1 viz, in which by reason of the physical and chemical properties of the respective materials under treatment and because of the specific conditions under which they are treated in a solid, semiliquid or fused state saidtools, implements,

containers, nozzles etc. are subjected to extraordinaril hi h mechanical stresses and to severe attac s t rough high temperaturese. g. up to 1000 centigradeand through strong acids such as sulfuric acid, nitric acid, hot lyes etc.

The industries under considerationinclude .those in which materials of high meltin point and articles of great hardness an toughness such as chilled steel castings, articles of metal, stone, carbon, hardruhber' etc. must be worked upon by turning, milling, drilling, cutting, shearing, sawin crushing, punching, pressing, rolling, ben 'ng, drawmg, die casting and other operatlons for -which heretofore tools of refined steel, and

often being provided with diamond-bits, and

requirements under consideration to a'higher degree and in a better and more comprehensive measure than it was possible heretofore with any known metal alloy both from a technical and an economical point of view.

Another object of my Invention is to provide a new method by which heavy duty arti cles of the character set forth can be readily manufactured directly from the said metal alloys intheir molten state and in such manner that the articles will require little or no finishing operations such grinding, polishing etc. 1

- Other objects of my invention will be dealt with hereinafter. i

The nature and scope of the invention is briefly outlined in the appended claims and its salient features will be morefullyunderstood from the following specification:

According to the results of my. extensive experiments metal alloys .for'the production as sharpening,

of articles having the aforesaid extraordi nary properties can be obtained by alloying tantalum in a molten state with a metal which does not combine'with carbon, i. e. which forms no carbides, such as cobalt, copper, nickel, or with an element of the platinum class such as palladium, iridium, osmium viz, in such proportions that the tantalum is the quasi-solvent and predominant constituent in the particularalloy, i. e. being PI'BSP ent in a proportion of over and preferably of 88-9 6%.

Hitherto it has only been possible to produce'mere conglomerations or mixtures of tantalum with other substances by a process of sintering. Such mixtures howevenwere not of a uniform texture,--were not obtainable in a redetermined com osition and consequentlally were unreliabl phgsical and chemical properties.

ccording tothis invention genuine tan-. talum alloys of the aforesaid composition (as distinguished from mere mixtures) are roduced in electrical high-frequency arc an resistanoe furnacesof types which unknown to metallurgical e erts. V

The tantalum to e alloyed may be used in its raw commercial form viz, powdered or I granulated. I

-By this invention shape and for any of the particular purposes concerned can be conveniently made b casting the molten tantalum alloy 'into carbonor graphite moulds.

, Practical have proved thatby 100 e in regard to their" articles of any desiredthe aforesaid metals which have no affinity for carbon as admixtures to the molten tantalum alloys are obtained which are distinguished by the properties of great act1v e (cutting) hardness, tenacity and which Wlll successfully withstand even high temperatures and strong acids.

In the course of my experiments tantalum has also been alloyed olectrot-hermically i. c. in a molten state with a carbide of a metal of the chromium group viz, with a carbon compound ofchromium, uranium, molybdenum, tungsten and again in such proportions that the tantalum remained the quasi-solvent predominant constituent in the alloy, being present therein in quantities of over'50% preferably of 88-96%.

Alloys of this composition which may be briefly termed for sake of convenience carbon tantalum alloys are distinguished from those referred to above which may be conveniently termed non-carbon tantalum alloys by a still greater cutting and wearing (active and passive) hardness of a diamondlike degree and will successfully withstand great heat and strong acids.

PracticaLtests have shown that cutting, milling, chasing, drilling tools, made by casting the molten alloy into moulds of carbon or graphite, can be successfully used for working upon articles of extraordinary hardness and toughness such as chilled steel castings, goods made of 12-14% manganese-steel etc, which hitherto have been considered as being beyond'the limits of hardness within which the respective articles could be shaped and finishedby steel tools, except by tools equipped with costly diamond-bits or made of vitrified abrasive substances ofcarborundum and the like.

In working upon materials of great hardness and toughness with tools made of tantalum alloys of the compositions hereinbefore set forth as in turning, milling and drilling, etc. the working and feeding speed and the thickness of the cut-ofi? chips or filings can be considerably increased thereby efiecting a material saving -in time and production costs. E. g. material such as 12-14% manganese steel has been turned at a working speed of 180 m. per minute, the feeding speed being 7 mm. per minute and the thickness of the filings 12 mm., the corresponding figures in turning chilled steel castings being 140 m. working speed per minute, 6 mm. feeding speed per minute and 12 mm; thickness of the filings.

Other electrothermically made in the course of my experiments which contained two additional substances as referred to above viz, one of the non-carbon group and one of the carbon group. By proportioning the amount of the admixtures to the molten tantalum solvent alloys of varying degrees of hardness and kinds of tantalum alloys have been tenacity can be obtained. Thus according to my invention alloys can be produced definitely and with any desired predeterminedmy invention possess the property of resisting high temperatures of say a red heat and strong acids. Thus such alloys can be successfully used in the manufacture of drawn wire, drawn tubing etc. viz, as materials for making drawing dies for draw benches, nozzles for metal extruding presses, tools for -repetition work and the hke and for appliances used in industries in which strong acids are employed.

Various changes and modifications may be made'in the composition of tantalum alloys specified hereinbefore and in the process of producing structural elements thereof without substantially departing from the salient features of my invention.

Since my latest experiments have shown that tantalum as the solvent and predominant element in the alloy may be wholly or partly substituted by corresponding quantities of niobium, a metal known in U. S. America as columbium which closely resembles tantalum chemically and is usually associated with the latter, I wish to expressly state that by briefl terming alloys of the compositions set fort .in the oregoing specificatlon and in the appended clalms tantalum alloys I wish thls term to be understood in a generic sense viz, comprising also alloys in which tantalum is replaced by the tantalum-like niobium metal or by an alloy of both said metals. What I claim is:

1. As a new article of manufacture a cast object composed of a metal alloy containing from 50 to 98% of tantalum and a carbide of a metal of the chromium group.

2. As a new article of manufacture a cast object composed of a metal alloy containing from 50 to 98% of tantalum, 20 to 0.5% of cobalt, and a carbide of a metal of the chromium group. 3. As a new article of manufacture a cast object composed of a metal alloy containing from .50 to 98% of tantalum, 20 to 0.5% of cobalt, 10 to 0.5% of copper, and a carbide of a metal of the chromium group.

4. Asa new article of manufacture a cast object composed of a metal alloy containing from 50 to 98% of tantalum, 20 to 0.5% of cobalt, 10 to 0.5% of copper, 5 to 0.5% of a metal of the platinum group including palladium, osmium, iridium, and a-carbide or a metal of the chromium group.

5. As a new article of manufacture a cast object composed of a metal alloy containin I from 50 to 98% of tantalum and a carbide o tungsten.

6. As a new article of manufacture a cast object composed of a metal alloy containing from 50 to 98% of tantalum, 20 to 0.5% of cobalt and a carbide of tungsten 7 As a new article of manufacture acast 1O object composed of a metal alloy containing from 50 to 98% of tantalum, 20 to 0.5% of cobalt, 10 to 0.5% of copper, and a carbide of tungsten.

8 As a new article of manufacture a cast object composed of a metal alloy containing from 50 to 98% of tantalum,- to 0.5% of cobalt, 10 to 0.5% of copper, 5 to 0.5% of a metal of the platinum group including palladium, osmium, iridium, and a carbide of 20 tungsten.

In testimony whereof I have signed my name to this specification.

WALTER SCHROBSDORFF. 

